The project is basically building a HN clone. So it should not be overly complex, although I'm not underestimating the work it'll take to build a polished product either.

As for the schedule, I'd like to start as soon as possible but I can be flexible. And the platform is up to you, although I have a strong preference for Ruby/Rails as I'm already somewhat familiar with it myself. And I'm also looking to use a JS framework on the client side, like Knockout or Ember for example.

Are you aware of the fact that HN is open source? There's also Reddit and Lamernews. You can pick one and re-skin for your purposes I suppose.

I am well aware of this, but Arc doesn't seem like a very popular language.. I could adapt Lamernews I suppose, I'll have to look into it. But in any case, the customisations I have in mind will probably require some outside coding help.